From 4c3d46238022f0c9955ae7e8b10c9f1716dd871a Mon Sep 17 00:00:00 2001 From: Francis Rowe Date: Wed, 04 Feb 2015 04:14:49 -0500 Subject: Documentation: implement theme, drastically improve readability --- (limited to 'docs/future/old.html') diff --git a/docs/future/old.html b/docs/future/old.html index eeaa96e..0f77a0a 100644 --- a/docs/future/old.html +++ b/docs/future/old.html @@ -16,256 +16,272 @@ -
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Development notes (old/obsolete notes)

- -
- -

- These are old (obsolete) notes that mare kept because they might become useful again in the future. -

- -
- -

Contents

- +
-
+

Development notes (old/obsolete notes)

+

+ For current notes, see index.html. +

-

X60 native graphics initialization (with backlight controls)

+

+ These are old (obsolete) notes that mare kept because they might become useful again in the future. +

+ +
-

- - This is now obsolete. A better way was found (included in libreboot): http://review.coreboot.org/#/c/6731/ - -

+
+ +

Table of contents

+ + +
+ +
+ +

X60 native graphics initialization (with backlight controls)

-

- Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher) -

-

- The fix below was done on 5320/6 (from review.coreboot.org) but should work just fine on later versions of 5320. -

-

- Native gpu init + backlight controls! (Fn keys). Also confirmed on X60 Tablet (1024x768) and X60 Tablet (1400x1050) -

-

- Add backlight controls: in src/mainboard/lenovo/x60/devicetree.cb, change gpu_backlight to 0x879F879E -

-

- That's all! This has also been backported into libreboot 5th release (line 1233 in src/mainboard/lenovo/x60/i915io.c). GNUtoo (Denis Carikli) - told me about the register BLC_PWM_CTL and that you could set it to control backlight. I read that address using devmem2 while running the VBIOS:
- # devmem2 0xe4361254 w -

-

- The change is also included in libreboot 6. -

-

- When doing this, it gave back that value. The same trick was used to get backlight controls for T60 (see #t60_native_notes). -

+

+ + This is now obsolete. A better way was found (included in libreboot): http://review.coreboot.org/#/c/6731/ + +

-

Further notes

- Reading 0xe4361254 (address) in Lenovo BIOS always yields FFFFFFFF, even when writing to it (and writing to it doesn't affect brightness controls). - 'mtjm' on IRC found that the buttons (Fn keys) control /sys/class/backlight/acpi_video0 which has no affect on 61254 (BLC_PWM_CTL). He says - intel_backlight has different values and uses the register. devmem2 works, needs checking lspci -vv for where the memory is mapped, - which is different than on coreboot; mtjm found that it was 0xec061254 on his machine (X60 Tablet), and the register value is different too. - This is relevant, because we still don't know how backlight controls are actually handled. We got it working by accident. We need to know more.. + Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher)

- Intel-gpu-tools may prove useful for further debugging: http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/ + The fix below was done on 5320/6 (from review.coreboot.org) but should work just fine on later versions of 5320.

- mtjm says 0xe4300000 is an MMIO region of the gpu (lspci -vv shows it), 0x61254 (BLC_PWM_CTL) is a documented register. Searching the kernel driver for backlight - shows that in intel_panel.c this register is used (there is an XXX comment about finding the right value, where recent kernels get it from. + Native gpu init + backlight controls! (Fn keys). Also confirmed on X60 Tablet (1024x768) and X60 Tablet (1400x1050)

- What we want to do is calculate a good value, instead of setting it in devicetree.cb. mtjm says about backlight physics: - it has a light source , uses pulse width modulation (PWM) to turn it on/off, dimming is done by spending less time on. - Note: this may not be correct; he says his understanding is based on how the Lenote yeeloong works. + Add backlight controls: in src/mainboard/lenovo/x60/devicetree.cb, change gpu_backlight to 0x879F879E

- mtjm goes on to say, that the register specifies the frequency used for PWM in its depending on the GPU core frequency, so it - might be possible to calculate it without hardcoded laptop-specific values. Therefore, I am supposed to find out the 'display core frequency' - (mtjm says there might be a register for it; also, it might be in 5320 or the replay code) and the PWM modulation frequency. - https://en.wikipedia.org/wiki/Backlight#Flicker_due_to_backlight_dimming + That's all! This has also been backported into libreboot 5th release (line 1233 in src/mainboard/lenovo/x60/i915io.c). GNUtoo (Denis Carikli) + told me about the register BLC_PWM_CTL and that you could set it to control backlight. I read that address using devmem2 while running the VBIOS:
+ # devmem2 0xe4361254 w

- phcoder (Vladimir Serbinenko) who is author of 5320 (review.coreboot.org) talks about 'duty cycle limit' and 'flickering frequency'. + The change is also included in libreboot 6. +

+

+ When doing this, it gave back that value. The same trick was used to get backlight controls for T60 (see #t60_native_notes).

-

Back to top of page

- -
+

Further notes

+

+ Reading 0xe4361254 (address) in Lenovo BIOS always yields FFFFFFFF, even when writing to it (and writing to it doesn't affect brightness controls). + 'mtjm' on IRC found that the buttons (Fn keys) control /sys/class/backlight/acpi_video0 which has no affect on 61254 (BLC_PWM_CTL). He says + intel_backlight has different values and uses the register. devmem2 works, needs checking lspci -vv for where the memory is mapped, + which is different than on coreboot; mtjm found that it was 0xec061254 on his machine (X60 Tablet), and the register value is different too. + This is relevant, because we still don't know how backlight controls are actually handled. We got it working by accident. We need to know more.. +

+

+ Intel-gpu-tools may prove useful for further debugging: http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/ +

+

+ mtjm says 0xe4300000 is an MMIO region of the gpu (lspci -vv shows it), 0x61254 (BLC_PWM_CTL) is a documented register. Searching the kernel driver for backlight + shows that in intel_panel.c this register is used (there is an XXX comment about finding the right value, where recent kernels get it from. +

+

+ What we want to do is calculate a good value, instead of setting it in devicetree.cb. mtjm says about backlight physics: + it has a light source , uses pulse width modulation (PWM) to turn it on/off, dimming is done by spending less time on. + Note: this may not be correct; he says his understanding is based on how the Lenote yeeloong works. +

+

+ mtjm goes on to say, that the register specifies the frequency used for PWM in its depending on the GPU core frequency, so it + might be possible to calculate it without hardcoded laptop-specific values. Therefore, I am supposed to find out the 'display core frequency' + (mtjm says there might be a register for it; also, it might be in 5320 or the replay code) and the PWM modulation frequency. + https://en.wikipedia.org/wiki/Backlight#Flicker_due_to_backlight_dimming +

+

+ phcoder (Vladimir Serbinenko) who is author of 5320 (review.coreboot.org) talks about 'duty cycle limit' and 'flickering frequency'. +

+ +

Back to top of page

+ +
+ +
+ +

T60 native graphics initialization (with backlight controls)

-

T60 native graphics initialization (with backlight controls)

+

+ + This is now obsolete. A better way was found (included in libreboot): http://review.coreboot.org/#/c/6731/ + +

+

+ Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher) +

+

+ The fix below was done on an earlier version of 5345 changeset (review.coreboot.org), but should work on the current version. it is included in libreboot 6 +

+

+ Add backlight controls: in src/mainboard/lenovo/t60/devicetree.cb, change gpu_backlight to 0x58BF58BE +

+

+ Hold on! Check ../misc/index.html#get_edid_panelname to know what LCD panel you have. This is important for the next step! +

-

- - This is now obsolete. A better way was found (included in libreboot): http://review.coreboot.org/#/c/6731/ - -

-

- Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher) -

-

- The fix below was done on an earlier version of 5345 changeset (review.coreboot.org), but should work on the current version. it is included in libreboot 6 -

-

- Add backlight controls: in src/mainboard/lenovo/t60/devicetree.cb, change gpu_backlight to 0x58BF58BE -

-

- Hold on! Check ../misc/index.html#get_edid_panelname to know what LCD panel you have. This is important for the next step! -

+

Supported panels

+

+ ../hcl/index.html#supported_t60_list. +

-

Supported panels

- ../hcl/index.html#supported_t60_list. + See index.html#lcd_i945_incompatibility.

+ +

Back to top of page

+ +
-

- See index.html#lcd_i945_incompatibility. -

- -

Back to top of page

- -
+
-

i945: 3D fix (based on 5927) for kernel 3.12+ on 5320

+

i945: 3D fix (based on 5927) for kernel 3.12+ on 5320

-

- - This is now obsolete. Merged in coreboot: http://review.coreboot.org/#/c/5927/ - -

+

+ + This is now obsolete. Merged in coreboot: http://review.coreboot.org/#/c/5927/ + +

-

This needs to be rewritten (or better organized, or deleted?). This is also now included in libreboot 6 (using the proper way, not the 7c0000 method which was a hack)

+

This needs to be rewritten (or better organized, or deleted?). This is also now included in libreboot 6 (using the proper way, not the 7c0000 method which was a hack)

-

- This was done on 5320/6 so far. The fix below is for 5320/6 which is now obsolete. This needs to be re-done for the latest version - of 5320. The fix below is (in practise) only for reference, therefore. -

+

+ This was done on 5320/6 so far. The fix below is for 5320/6 which is now obsolete. This needs to be re-done for the latest version + of 5320. The fix below is (in practise) only for reference, therefore. +

-

- See #x60_cb5927_testing for the original (and current) fix, for the replay code. Now we want - to implement that on top of http://review.coreboot.org/#/c/5320 - which is the current code for native graphics initialization on i945. -

+

+ See #x60_cb5927_testing for the original (and current) fix, for the replay code. Now we want + to implement that on top of http://review.coreboot.org/#/c/5320 + which is the current code for native graphics initialization on i945. +

-

- src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320: 5320_7c0000_gma.c (rename it to gma.c, - replacing the current one). -

+

+ src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320: 5320_7c0000_gma.c (rename it to gma.c, + replacing the current one). +

-

- The above is a hack (as is the original). A better (more correct) method is implemented in later versions of 5927, so - that should also be adapted for 5320. For now, you can use the above fix. -

+

+ The above is a hack (as is the original). A better (more correct) method is implemented in later versions of 5927, so + that should also be adapted for 5320. For now, you can use the above fix. +

-

- The correct way to do it is to set gtt address to (end of stolen memory - gtt size), which is what later versions of 5927 do (successfully). -

+

+ The correct way to do it is to set gtt address to (end of stolen memory - gtt size), which is what later versions of 5927 do (successfully). +

-

- Here is some debugging output using intel_gpu_tools v1.2-1 (from trisquel repositories) using tool "intel_gtt": -

+

+ Here is some debugging output using intel_gpu_tools v1.2-1 (from trisquel repositories) using tool "intel_gtt": +

- + + +

Back to top of page

+ +
+ +
+ +

i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)

-

Back to top of page

+

+ + This is now obsolete. Merged in coreboot: http://review.coreboot.org/#/c/5927/ + +

-
+

The latest version as-is (5927/11) has not been tested by me yet. Always boot with 'drm.debug=0x06' kernel parameter when testing this.

-

i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)

+

+ This is the fix for 3D on kernel 3.12 and higher on i945 (ThinkPad X60 in this case). This is for the replay code. + Libreboot 5th release has a version of this backported already (based on 5927/3 using the '7c0000' hack). +

-

- - This is now obsolete. Merged in coreboot: http://review.coreboot.org/#/c/5927/ - -

+

+ + The replay code is obsolete (see 5320 changeset on review.coreboot.org for better version + which supports more machines/screens, and then 5345 for T60). Information here for reference since that is where the fix was first applied. + +

-

The latest version as-is (5927/11) has not been tested by me yet. Always boot with 'drm.debug=0x06' kernel parameter when testing this.

+

+ Read the information on http://review.coreboot.org/#/c/5927/. +

-

- This is the fix for 3D on kernel 3.12 and higher on i945 (ThinkPad X60 in this case). This is for the replay code. - Libreboot 5th release has a version of this backported already (based on 5927/3 using the '7c0000' hack). -

+

+ For historical purposes, here is a collection of IRC logs that once existed on this page, related to the issue: + kernel312_irc. +

-

- - The replay code is obsolete (see 5320 changeset on review.coreboot.org for better version - which supports more machines/screens, and then 5345 for T60). Information here for reference since that is where the fix was first applied. - -

+

+ PGETBL_CTL differs between VBIOS (-) and native graphics init (+).
-

- Read the information on http://review.coreboot.org/#/c/5927/. -

+ - PGETBL_CTL: 0x3ffc0001
+ + PGETBL_CTL: 0x3f800001 +

+

GTT (graphics translation table) size is PGETBL_save, max 256 KiB. BSM (Base of Stolen Memory) is given by the bios.

+ + + +

Back to top of page

+ +
+ +
+

- For historical purposes, here is a collection of IRC logs that once existed on this page, related to the issue: - kernel312_irc. + Copyright © 2014, 2015 Francis Rowe <info@gluglug.org.uk>
+ This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. + A copy of the license can be found at ../license.txt.

- PGETBL_CTL differs between VBIOS (-) and native graphics init (+).
- - - PGETBL_CTL: 0x3ffc0001
- + PGETBL_CTL: 0x3f800001 + This document is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information.

- -

GTT (graphics translation table) size is PGETBL_save, max 256 KiB. BSM (Base of Stolen Memory) is given by the bios.

- - - -

Back to top of page

- -
- -

- Copyright © 2014 Francis Rowe <info@gluglug.org.uk>
- This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. - A copy of the license can be found at ../license.txt. -

- -

- This document is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information. -

+ +
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